Assuming "one whole number 2/5 of soil for his garden" mean 1+2/5(equal to 7/5) then 1/5 of the original garden soil would be:
1/5 * 7/5 = 7/25
Then you need to add the first sum(7/5) with the second sum(7/25) to get the total soil. The calculation would look like this:
7/5 + 7/25= 35/25 + 7/25= 42/25= 1 + 17/25
